Question 1208795
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As tutor greenestamps points out, the missing term <font size=4><u>could be</u></font> 484.5
That's assuming the sequence follows a polynomial function.
That particular function is f(n) = 0.25n^4 - 3.25n^3 + 14.75n^2 - 13.25n + 445.5 where n is an integer that starts at n = 1
Plugging n = 1 gives the first term 444
n = 2 gives the second term 456
n = 3 gives the third term 471
etc



However, we could have a situation as discussed at this link
<a href="https://www.algebra.com/algebra/homework/Sequences-and-series/Sequences-and-series.faq.question.1188392.html">https://www.algebra.com/algebra/homework/Sequences-and-series/Sequences-and-series.faq.question.1188392.html</a>
Each term <font size=4><u>could be</u></font> equal to the previous term plus the sum of the digits.
444+(4+4+4) = 456
456+(4+5+6) = 471
471+(4+7+1) = <font color=red>483 (??)</font>
483+(4+8+3) = 498
498+(4+9+8) = 519
I put question marks after the 483 because it's quite possible that another value could fit in that slot. 
There are probably many other ways to generate the sequence given, and hence many values to replace the question mark in your given sequence.




Check out this similar problem
<a href="https://www.algebra.com/algebra/homework/Sequences-and-series/Sequences-and-series.faq.question.1195799.html">https://www.algebra.com/algebra/homework/Sequences-and-series/Sequences-and-series.faq.question.1195799.html</a>
On that link I try to find the next few terms in the sequence 1,2,4,...
It turns out there are at least 3 different possible answers for that question. There may be infinitely many answers. 
This is more evidence that vague questions like this are very flawed. There needs to be more context provided. 
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